Extraction means for producing coffee for a coffee machine

ABSTRACT

An extraction means for the producing of coffee for a coffee machine is equipped with a brewing cylinder ( 2 ) for the receiving of coffee powder, whereby the same is reciprocably adjustable between pre-determined positions in its axis direction in co-operation with a drive means ( 4 ). Two pistons ( 31, 32 ) coaxially adjustable relative to one another are located in this brewing cylinder ( 2 ). The brewing cylinder ( 2 ) incorporates a cylinder section ( 20 ), and an additional part ( 22 ) is also envisaged. The additional part ( 22 ) is moveably located at the end of the brewing cylinder ( 2 ) that can be closed by the first piston ( 31 ) and equipped with a filler opening ( 24 ) for the insertion of the coffee powder. In this way the construction length of the extraction means can be shortened.

The invention concerns an extraction means for producing coffee for a coffee machine according to the main description of the enclosed claim 1.

An extraction means is described in EP-B-0 299 399. It incorporates an adjustable brewing cylinder for the receiving of coffee powder working in co-operation with a drive means being reciprocably moveable along a longitudinal guide between pre-determined positions as well as two pistons, adjustable relative to one another and positioned coaxially in relation to the brewing cylinder. The coffee powder is inserted through a side filler opening of the brewing cylinder, whereby an end of the brewing cylinder open at the front is held closed by one of the two pistons, i.e. the substantially fixedly installed first piston. During the adjusting of the brewing cylinder in one direction, via the first piston, the first piston defines a front-side brewing chamber together with the second piston that is moved by the brewing cylinder and ensures compression of the inserted coffee powder. In this position boiling water is inserted into the brewing chamber through one piston and pumped through the compressed coffee powder, whereafter the coffee produced in this way is conveyed to an outlet of the coffee machine through the other piston. During the subsequent adjusting of the brewing cylinder in the other direction the used coffee powder is ejected through the second piston from the brewing cylinder end that has in the meantime been released by the first piston.

Another generic means according to publication U.S. Pat. No. 5,275,089 also envisages two pistons that can be adjusted in relation to the brewing cylinder and a block incorporating a filler opening for the insertion of coffee powder. On the inside of this cylinder shaped block a sleeve and one piston are located and can be moved in a longitudinal direction. In the filling position this block is positioned at the rear sleeve part and abuts against the front side of the same together with the other piston, whereas the same are separate from one another in the ejection position. In the brewing position the piston that is positioned near the additional part comes to rest inside the cylinder part. As this sleeve within the block is a necessary requirement and has to be displaceable just like the piston associated with the same the construction of this extraction means is complicated.

The task of this invention is to further improve the already proven extraction means of the type mentioned above in a more space saving way.

This task is solved in accordance with the invention by an extraction means with the characteristics of claim 1.

Further preferred embodiments of the extraction means of this invention form the subject of the subclaims.

With the dividing of the machine according to this invention into the brewing cylinder and an additional part, of which one forms the actual brewing cylinder section enclosing the brewing chamber that can be adjusted via the drive means, and where the additional part is located at the end of the brewing cylinder that can be closed by the first piston, whereby the same is equipped with the filler opening for the insertion of the coffee powder, whereby the two cylinder parts are pushed together on the facing side and adjusted together during the adjusting of the brewing cylinder in one direction, and whereby the same can be separated from one another during the adjusting of the brewing cylinder section in the other direction, so that an axial gap is created, through which the used coffee powder can fall out, the length of the brewing cylinder as well as the lift of the second piston required for the ejecting of the used coffee powder can be shortened, so that the overall length of the extraction means is also reduced.

In addition the ejection process is shortened, and lastly also some material for the manufacture of the shortened parts is saved. Furthermore the additional part incorporating the filler opening, which is largely uninvolved with the actual brewing process, can be manufactured from a cheaper material such as plastic during a more simple process than that required for the brewing cylinder consisting of stainless steel, in which no side filler opening has to be installed.

The invention will now be described in more detail with reference to the drawings, whereby:

FIG. 1 shows a perspective view of an example of an embodiment of an extraction means of this invention for a coffee machine;

FIG. 2 shows a cross-section along line 11-11 in FIG. 3;

FIG. 3 shows a longitudinal section of the extraction means of FIG. 1 in a starting position;

FIG. 4 shows a longitudinal section of the extraction means of FIG. 1 in a brewing position;

FIG. 5 shows a longitudinal section of the extraction means of FIG. 1 in an ejection position;

FIG. 6 shows a perspective view of a further embodiment of an extraction means of this invention; and

FIG. 7 shows a view of the example of an embodiment according to FIG. 6, where the associated handle has been omitted.

FIGS. 1 to 5 show an extraction means 1 for the producing of coffee which is used within an automatic coffee machine. It incorporates a brewing cylinder 2 with a cylinder section 20 and an axial cylindrical additional part 22 that can be added to the same as will be described in more detail below. One of these parts, the pipe-shaped brewing cylinder section 20, is affixed to a sledge 3 and is reciprocably positioned together with the same in co-operation with a drive means 4 in its axis direction between pre-determined positions, whereby the same is held on two guide rods 5, 6. The guide rods 5, 6 are fitted into a holder 7, 8 at each end.

The drive means 4 incorporates a drive spindle 9 which acts upon the sledge 3, which is bearingly and rotatingly positioned in the two holders 7, 8, and which stands in drive connection via a belt drive 11 with a drive motor 10, preferably a DC motor (direct current motor). The axis of the drive spindle 9 extends along a central longitudinal level of the extraction means 1 which extends between the two guide rods 5, 6.

In the position of the sledge 3 illustrated in FIG. 3 the additional part 22 abuts against the brewing cylinder section 20 which is fixedly connected with a front-side open end 21 of the sledge 3, whereby the same is equipped with a side filler opening 24 for the insertion of coffee powder into the hollow brewing cylinder space. The additional part 22 is connected to a guide part 23 and loosely and moveably held on the guide rods 5, 6 together with the same over the drive spindle 9 (although it is not driven by the drive spindle 9). Two springs 25, 26 (see FIG. 2) integrated into the guide rods 5, 6 act upon the guide part 23, whereby the same press the guide part 23 against a shoulder 27, 28, each radially orientated in relation to the guide rod 5, 6 and for example screwed to the same, which can also axially join the additional part 22 and the cylinder section 20 in this position.

Two pistons 31, 32, relatively adjustable in relation to one another, are coaxially associated with the brewing cylinder 2, which is adjustable in its axis direction. The first, substantially fixed piston 31 consists of two parts. Whilst one piston part 33 is fixedly installed within the holder 7 the other piston part 34 is slightly axially moveable in relation to, and spring-supported against the same. A compression spring 35 is located between the two piston parts 33, 34. The two piston elements 33, 34 are connected to one another along their circumference by an annular seal 37 equipped with a U-shaped cross-section, which is affixed around both piston parts 33, 34 at its ends. The compression spring 35 aims to push the two piston parts 33, 34 apart and expands the seal 37 in a longitudinal direction. When the moveable piston part 34 is pressed against the fixed piston part 33 against the direction of the force of the spring 35 the seal 37 is pressed radially outwards and therefore into its sealing function position. The first piston 31 thereby closes off the front-side open end of the brewing cylinder 2.

The second piston 32 is moveably positioned within the brewing cylinder section 20. An annular seal 38 is located around the circumference of this piston 32. The second piston 32 projects from the brewing cylinder 20 through a front-side brewing cylinder end part 39 with its piston rod 40. The piston rod 40 is equipped with a head 41, preferably made of plastic, incorporating a circumferential groove 42 at its end, with which it can engage a holding means 43 located on the holder 8. The holding means 43 incorporates rod-shaped spring elements 44 co-operating with the circumferential groove 42, which extend substantially tangential to the circumferential groove 42, and which can be pressed apart during the engaging process. It is of course also possible to use a different engaging means. In the position illustrated in FIG. 3 the second piston 32 is located near the end part 39 and the piston rod 40 engages the holding means 43.

In the starting position of the extraction means 1 illustrated in FIG. 3 the ground coffee powder can be inserted into the brewing cylinder 2 through the side filler opening 24 that is connected to a coffee grinder. Within the additional part 22 two opposing side filler openings 24 that correspond with one grinder each can be advantageously envisaged.

Once a defined portion of coffee powder has been inserted into the chamber defined by the two pistons 31, 32 the brewing cylinder 2, and the additional part 22 the sledge 3 are now moved together with the brewing cylinder section 20 by the drive means 4 in the direction of the arrow A of FIG. 3, whereby the additional part 22 abutting against the cylinder section 20 is also moved together with the guide part 23, whereby the same remains pressed against the brewing cylinder section 20 by the springs 25, 26 integrated into the guide rods 5, 6. The cylinder section 20 as well as the additional part 22 are pushed over the first piston 31 (whilst its two piston parts 34, 33 are compressed) into a position illustrated in FIG. 4. However, the second piston 32 is also carried along by the brewing cylinder 2 moving in the direction of the arrow A whilst the head 41 is disengaged from the holding means 43 and moved a certain distance in the direction of the fixed first piston 31. In this way the chamber containing the coffee powder is compressed to a pre-determined size and the coffee powder is compressed, i.e. compacted.

In this brewing position illustrated in FIG. 4 the actual brewing process can be carried out in that boiling water or steam is pumped into the hollow space sealed by the seals 37, 38 and through the coffee powder through one piston (for example through the channels 32′ of the second piston 32), and in that the produced coffee is conveyed to an outlet of the coffee machine that is not visible in the drawing through the other piston (for example through channels 31′ of the first piston 31).

Following the completion of the brewing process the sledge 3 is moved together with the brewing cylinder section 20 in the other direction (arrow direction B in FIG. 4) by the drive means 4. The additional part 22 connected with the guide part 23 initially remains pressed against the brewing cylinder section 20 and is moved back together with the same by the action of the spring 25, 26 until the guide part 23 abuts against the shoulders 26, 27 connected to the guide rods 5, 6. The additional part 22 equipped with the filler opening 24 (i.e. the filler openings 24) that has come to a standstill will now be separated from the brewing cylinder section 20 that moves further together with the sledge 3 in the direction of the arrow B, and an axial gap is therefore created between these two parts. With the brewing cylinder section 20 the second piston 32 is also displaced in the direction of the arrow B until the head 41 once more engages the holding means 43. However, as the brewing cylinder section 20 is moved onwards in the direction of arrow B towards the holder 8 together with the sledge 3 until a facing surface 46 of the brewing cylinder end part 39 abuts against a counter surface 47 of the head 41 engaged in the holding means 43 (see FIG. 5) a relative movement between the second piston 32 and the brewing cylinder section 20 occurs, and the used coffee powder, i.e. the coffee grounds, is ejected from the brewing cylinder section 20 into the axial gap between the sections 20, 22 by the second piston 32 and falls into a catchment container located below the same (not illustrated in the drawing).

The division of the brewing cylinder 2 according to this invention into the cylinder section 20 located along a longitudinal guide (guide rods 5, 6) and the additional part 22, of which one forms the actual brewing cylinder section 20 enclosing the brewing chamber and adjustable by the drive means 4, and whereby the additional part 22 is equipped with the filler opening 24 for the insertion of coffee powder, whereby the same are pressed against one another with their front sides and moved in a direction A during the adjusting of the brewing cylinder section 20, and separated from one another during the adjusting of the brewing cylinder section 20 in the other direction B, so that an axial gap is created, through which the used coffee powder can be ejected, means that the length of the brewing cylinder 2 as well as the lift of the second piston 32 required for the ejecting of the used coffee powder can be shortened, so that the overall length of the extraction means 1 is also reduced.

In addition the ejection process is shortened, and lastly also some material for the manufacture of the shortened parts is saved. Furthermore the additional part 22 incorporating the filler opening 24, which is largely uninvolved with the actual brewing process, can be manufactured from a cheaper material such as plastic during a more simple process than that required for the brewing cylinder consisting of stainless steel, in which no side filler opening has to be installed.

It is of course possible to envisage different embodiments of the extraction means of this invention. It is for example possible to realise an alternative drive means to that illustrated in the drawings.

The use of a DC motor of the type of a staged motor enables a very accurate and repeatable position adjustment with a constant compression pressure, and constantly sized ground coffee portions to be ejected etc.

According to FIGS. 6 and 7 the means for the front-side pressing of the cylinder section 20 against the additional part 22 for the inserting of the coffee powder with at least one spring 25, 26 can be replaced with a mere abutment of the cylinder section against the additional part.

Identically shaped parts such as those of the extraction means according to FIG. 1 to FIG. 5 have been allocated identical reference numbers and will not be described in detail below.

The cylinder-shaped additional part 22 abuts against the brewing cylinder 2 during the inserting of coffee powder on one side as shown in FIG. 3, and encloses the piston 31 on the opposite side, so that a chamber is formed. The ground coffee can then be inserted through the filler opening 24 in the additional part 22 into the chamber formed in this way from a grinder not shown in detail.

After this the cylinder section 20 is pushed further against the fixed piston 31 together with the piston 32 in an analogue fashion as also shown in FIG. 3 until the cylinder section 20 encloses this piston 31. At the same time the additional part 22 is moved in the same direction until the same comes to rest on the rear side of the piston. In this position the coffee powder is compressed into grounds and hot water is subsequently pressed through the pistons to produce the coffee.

Following completion of the brewing process the cylinder section 20 is first retracted from the piston 31. At a certain distance the piston 32, and by association of slide rods 27′, 28′ positioned parallel with the guide rods 5, 6 and the relevant shoulders also the additional part 22, is also pulled as far as the filling position, i.e. to the front side of the piston 31 (see FIG. 5). As soon as the cylinder section 20 has reached the end position near the holding means 8 the coffee grounds are ejected by the piston 32.

In this way it is possible to provide a simple solution for the adjustment of the additional part 22 without creating operational disadvantages. 

1-12. (canceled)
 13. Extraction means for producing coffee for a coffee machine, with a brewing cylinder (2) incorporating a cylinder section (20) adjustable by a drive means (4), for the receiving of coffee powder, whereby the same can be reciprocably moved in its axis direction in co-operation with the drive means (4) between pre-determined positions, with two pistons (31, 32) adjustable in relation to the brewing cylinder (2) and relative to one another, and with an additional part (22) incorporating at least one filler opening (24) for the inserting of the coffee powder, which abuts against the front side of the cylinder section (20) in the filling position, whereby the same are separated from one another in the ejecting position, for the forming of an axial gap for the removing of the used coffee grounds, whereby the piston (31) adjacent to the additional part (22) comes to rest within the cylinder section (20) in the brewing position, wherein the additional part (22) is moveably positioned with the at least one filler opening (24), whereby the same encloses the piston (31) in the filling position and forms a chamber together with the cylinder section (20) and the pistons (31, 32).
 14. Extraction means according to claim 13, wherein the reciprocal movement of the additional part (22) can be effected either by the brewing cylinder (2) alone or by the same together with additional means.
 15. Extraction means according to claim 13, wherein the brewing cylinder section (20) that can be adjusted by the drive means (4) is moveably affixed to and carried upon a sledge (3) in turn affixed to two side guide rods (5, 6) and adjustable via a drive spindle (9), whereby the additional part (22) is also moveably held together with a guide part (23) upon the guide rods (5, 6).
 16. Extraction means according to claim 14, wherein the means for the displacing and for the front-side pressing of the cylinder section (20) against the additional part (22) incorporates at least one spring (25, 26), whereby the additional part (22) is adjustable in one direction (A) by the cylinder section (20) adjusted by the drive means (4) against the force of the spring (25, 26), and retractable in the other direction (B) by the force of the spring (25, 26) up to a shoulder (27, 28).
 17. Extraction means according to claim 13, wherein the first piston (31) consists of two parts and incorporates a moveable piston part (34) that is spring-supported against a fixed piston part (33), whereby the two piston parts (33, 34) are connected with one another around their circumference by an annular seal (37) with a U-shaped cross-section, and in that the seal (37) can be radially pressed apart when the moveable piston part (34) is pressed against the fixed piston part (33), so that the same can be brought into its sealing function position.
 18. Extraction means according to claim 13, wherein the second piston (32) engages a fixed holding means (43) with its piston rod (40) projecting from the brewing cylinder section (20), and is therefore reciprocably moveable relative to the axial gap in the direction of the brewing cylinder section (20) moving away from the additional part (22).
 19. Extraction means according to claim 18, wherein the piston rod (40) is equipped with a head (41) incorporating a circumferential groove (42) with which the same can be inserted between rod-shaped spring elements (44) of the holding means (43) engageable with the circumferential groove (42) and extending tangentially in relation to the same circumferential groove (42).
 20. Extraction means according to claim 13, wherein the cylinder section (20) can be retracted following the completion of the brewing process, and in that the piston (32), and through association of slide rods (27′, 28′) and relevant shoulders positioned parallel to the guide rods (5, 6) the additional part (22) also, can be moved up to the filling position after moving a certain pre-determined distance.
 21. Extraction means according to claim 13, wherein the drive means incorporates a staged motor.
 22. Extraction means according to claim 13, wherein the two pistons (31, 32) incorporate channels (31′, 32′), whereby boiling water or steam can be added under pressure via the channels (31′, i.e. 32′) of one piston (31, i.e. 32) into the brewing chamber, and therefore into the compacted coffee powder, defined at the front by the pistons (31, 32), and in that the produced coffee can be conveyed to an outlet of the coffee machine through the channels (32′, i.e. 31′) of the other piston (32, i.e. 31).
 23. Extraction means according to claim 13, wherein the cylinder part (22) that is equipped with a filler opening (24) consists of plastic.
 24. Extraction means according to claim 13, wherein a displacement of the cylinder section (20) away from the piston (31) occurs following the completion of the brewing process, and in that the association of slide rods (27′, 28′) positioned parallel to the guide rods (5, 6) and the relevant shoulders also results in a displacement of the additional part (22) up to the filling position, i.e. up to the front side of the piston (31). 